(100e) Preconditioning Effects Upon Co-Containing Pt-Promoted and Unpromoted Fischer-Tropsch Catalysts

Cronauer, D., Argonne National Laboratory
Elam, J. W., Argonne National Laboratory
Kropf, A. J., Argonne National Laboratory
Libera, J. A., Argonne National Laboratory

As part of a research program to create, prepare, and evaluate Fischer-Tropsch (FT) catalysts, active catalysts formed by atomic-layer deposition [ALD] of major components were demonstrated.  ALD-deposited Co on a silica support was more effective than a similar catalyst deposited upon a support of ALD-deposited Al2O3 on silica. The activities of Co on Al2O3 catalysts prepared by the Center for Applied Energy Research (CAER) were compared with those of these catalysts.  The addition of Pt, by either ALD or incipient wetness techniques, as a promoter of Co-containing catalyst has been shown to primarily affect the catalyst pre-conditioning step. CO conversion results were consistent with previously reported 1 TPR-XANES/EXAFS experiments observing the nature of the chemical transformations occurring during the activation of cobalt-based FT catalysts in H2.  Specifically, there exists a 2-step reduction process involving Co3O4 to CoO to Co0 transformations. The extent of catalyst preconditioning was strongly affected by the reduction temperature and the level of Pt deposition. A continuous-flow catalytic-bed unit was used for this FT study.  The gaseous feed consisted of either a 1:1 or 2:1 molar blend of H2:CO, and the experiments were carried out at temperatures ranging from about 260°C to 300°C, pressures averaging 13.1 MPa (190 psia), a gas feed rate of about 15 mL/min, and a catalyst charge of 0.1 g.

1. G. Jacobs, Y. Ji, B.H. Davis, D.C. Cronauer, A.J. Kropf, C.L. Marshall, Applied Catalysis A, General  333 (2007),  177-191